Compact dual packer with locking dogs

Abstract

A compact, retrievable packer has a unitary mandrel body which is intersected by one or more longitudinal production bores. The running length of the packer is reduced and premature set/release are prevented by a lock assembly which releasably locks the lower setting wedge to the packer mandrel. The lock assembly includes one or more locking dogs mounted within mandrel pockets for radial extension and retraction. The locking dogs are extended into an annular slot formed between a retainer collar and the packer mandrel. The lower setting wedge is secured by threaded engagement with the retainer collar. When the locking dogs are extended, the lower setting wedge is blocked against longitudinal displacement, thereby opposing setting forces applied to anchor slips. The locking dogs are held in the locked position by brace rods which are releasably blocked by a shifting sleeve mounted in one of the packer mandrel bores.

What is claimed is: 
     
       1. A well packer comprising, in combination: a body mandrel having a bore defining a longitudinal flow passage;   a seal element assembly mounted on said body mandrel;   an anchor slip assembly mounted on said body mandrel;   force transmitting apparatus movably coupled to said seal element assembly and said anchor slip assembly for extending said seal element assembly and said anchor slip assembly into set engagement against a well bore;   tubular wedge apparatus coupled to the body mandrel 13 and engagable by said anchor slip assembly for limiting longitudinal travel of said anchor slip assembly and reacting setting forces transmitted thereto; and,   releasable lock apparatus coupling the tubular wedge apparatus to the body mandrel for opposing longitudinal movement of the tubular wedge apparatus relative to the body mandrel.   
     
     
       2. A well packer as defined in claim 1, said releasable lock apparatus comprising: a locking dog movably mounted on the body mandrel for extension and retraction into and out of engagement with the tubular wedge apparatus;   a shifting sleeve releasably secured within the body mandrel bore; and,   a brace rod projecting through the body mandrel, said brace rod having a first end portion engagable against the shifting sleeve and a second end portion engagable against the locking dog for blocking retraction of the locking dog out of locking engagement with the tubular wedge apparatus.   
     
     
       3. A well packer as defined in claim 1, said releasable lock apparatus comprising: a radial slot intersecting said body mandrel and communicating with the longitudinal flow passage;   a pocket formed in said tubular wedge apparatus;   a locking dog having a first body portion and a second body portion, said locking dog being radially movable from a locked position in which the first body portion and the second body portion are disposed in the body mandrel slot and the wedge pocket, respectively, to a released position in which the second body portion is retracted out of the wedge pocket;   a brace rod engaging the locking dog and projecting through the body mandrel slot;   a shifting sleeve disposed in the longitudinal flow passage in blocking engagement with the brace rod; and,   at least one shear pin releasably securing the shifting sleeve to said body mandrel.   
     
     
       4. A well packer as defined in claim 1, said tubular wedge apparatus including a retainer collar secured to said wedge, said retainer collar having a tubular sidewall radially spaced from said packer mandrel thereby defining an annular pocket, and having an inwardly projecting shoulder disposed in slidable engagement with said body mandrel, and said releasable lock apparatus including a locking dog mounted for extension and retraction relative to said packer mandrel, said locking dog being extendable into and retractable out of said annular pocket. 
     
     
       5. In a retrievable well packer of the type including a body mandrel having a bore defining a longitudinal flow passage, an anchor slip assembly and a seal element assembly movably mounted on said mandrel, and tubular wedge apparatus mounted on said mandrel for engagement with the anchor slip assembly for limiting longitudinal travel of the anchor slip assembly and for opposing setting forces applied to the anchor slip assembly, the improvement comprising: a locking dog movably mounted on the body mandrel for extension and retraction into and out of engagement with the tubular wedge apparatus;   a shifting sleeve releasably secured within the body mandrel bore; and,   a brace rod projecting through the body mandrel, said brace rod having a first end portion engagable against the shifting sleeve and a second end portion engagable against the locking dog for blocking retraction of the locking dog out of locking engagement with the tubular wedge apparatus.   
     
     
       6. An improved packer as defined in claim 5, said tubular wedge apparatus including a retainer collar secured to said wedge, said retainer collar having a tubular sidewall radially spaced from said packer mandrel thereby defining an annular pocket, and having an inwardly projecting shoulder disposed in slidable engagement with said body mandrel, and said releasable lock apparatus including a locking dog movably mounted on said mandrel, said locking dog being extendable into and retractable out of the annular pocket. 
     
     
       7. In a subterranean well having a casing embedded within a producing formation, a packer engaging said casing and having a mandrel supporting production equipment within said well, said mandrel having a longitudinal bore defining a production flow passage, force transmitting means mounted on said packer mandrel for setting an anchor slip assembly and seal element assembly against said casing, and tubular wedge apparatus disposed for engagement with said anchor slip assembly for limiting longitudinal travel of said anchor slip assembly and for opposing setting forces applied to said anchor slip assembly, the improvement comprising: releasable lock apparatus coupling the packer mandrel to the tubular wedge apparatus for opposing longitudinal movement of the packer mandrel relative to the tubular wedge apparatus.   
     
     
       8. The improvement as defined in claim 7, said releasable lock apparatus comprising: a retainer collar secured to said wedge, said retainer collar having a tubular sidewall radially spaced from said mandrel thereby defining an annular pocket, and having an inwardly projecting shoulder disposed in slidable engagement with said packer mandrel; and,   releasable lock apparatus including a movable lock member projecting transversely through the packer mandrel, said movable member being extendable into and retractable out of said annular pocket.   
     
     
       9. A well packer as defined in claim 7, said releasable lock apparatus comprising: a radial slot intersecting said packer mandrel and communicating with the longitudinal flow passage;   a pocket formed in said tubular wedge apparatus;   said movable lock member having a first body portion and a second body portion, said lock member being extendable to a lock position in which the first body portion and the second body portion are disposed in the packer mandrel slot and the wedge pocket, respectively, to a release position in which the second body portion is retracted out of the wedge pocket;   a brace rod engagable with the lock member and projecting through the packer mandrel slot;   a shifting sleeve disposed in the longitudinal flow passage in blocking engagement with the brace rod; and,   at least one shear pin releasably securing the shifting sleeve to said packer mandrel.   
     
     
       10. In a well packer of the type having a body mandrel intersected by a longitudinal bore defining a production flow passage and having a tubular wedge disposed for engagement by a movable anchor slip assembly for limiting longitudinal travel of the anchor slip assembly and for reacting setting forces applied to the anchor slip assembly, the improvement comprising: a locking dog movably mounted on the body mandrel for extension and retraction into and out of engagement with the tubular wedge;   a shifting sleeve releasably secured within the body mandrel bore; and,   a brace rod projecting through the body mandrel, said brace rod having a first end portion engagable against the shifting sleeve and a second end portion engagable against the locking dog for blocking retraction of the locking dog out of locking engagement with the tubular wedge apparatus.